I got my amp with a speaker cabinet for $450 used. The fan had already been replaced once with a hard-wired 120 volt fan instead of the variable voltage DC fan that it came with. Apparently, those fans and the usage sensors had the tendency to fail often. My two questions are: Where would be the best place to find a new 120 volt 3" fan, and Does anybody know what size case screws the head uses? A couple of them were stripped.